The polar bears were waiting for the ice to refreeze so they could hunt for seals. The photos were taken by Larry Schweiger, president and CEO of the National Wildlife Federation. He just returned from the Hudson Bay in Canada, where he and scientists observed the polar bears. His polar bear photos are available for sharing (credit the National Wildlife Federation).

Photo by Larry Schweiger / NWF.

Researchers are reporting the local population of polar bears could collapse in the space of a year or two if conditions are bad enough. The bears fast during the summer months when ice on the Bay melts. But warming temperatures mean the ice is gone for a longer period each summer—forcing the bears to go hungry an average of nearly three more weeks than in the 1970s.

Photo by Larry Schweiger / NWF

Until the last few decades, the polar bears in Hudson Bay could have counted on the ice having formed earlier than recent trends—ending their summer fast and allowing them to hunt for seals. Now, more bears are visibly thin and fewer cubs are surviving as their ice, despite annual variation, continues it’s overall downward trend.

Photo by Larry Schweiger / NWF

These bears live toward the southern edge of polar bears’ range—and are a warning of what is expected to be in store for some polar bear populations further north if we do not act quickly to reduce carbon emissions. Already, populations of polar bears in Hudson Bay and in the Beaufort Sea are known to have declined in numbers and condition in recent years as ice availability has diminished. They are a call to action on climate change.

UPDATE: While the temperatures were in the mid-thirties when the group from the National Wildlife Federation was in Churchill, Canada in November 2013, the main stress from the warming temperatures is the long-term trend of longer ice-free periods when polar bears cannot hunt for seals. The polar bears in the photos would have been waiting for the ice to refreeze so that they could once again hunt for food. The text above has been corrected to reflect that.

The polar bears photographed are a part of the western Hudson Bay population that scientists are describing as underweight and stressed from the lengthening time without food. When the NWF group visited the Northern Studies Centre research facility, the scientists there confirmed that bears are underweight by an average of about 85 pounds since the early 1980s.

Although ice conditions and bear health change from year to year, what is important is the long-term decline in this population attributed to declining survival and reproduction. The decline of polar populations in western Hudson Bay, as well as the Beaufort Sea, is a concern for many other polar bear populations if carbon emissions are not dramatically reduced.